The semiconductor integrated circuit (IC) industry has produced a wide variety of devices to address issues in a number of different areas, including radio frequency (RF) communications. While growing in popularity, improving RF integrated circuits puts particular demands on the semiconductor process. Some RF circuits employ thick metal layers, even ultra-thick metal layers (UTM) for inductive and other properties. However, some traditional semiconductor processing techniques do not readily scale for use with UTM.
In some instances, semiconductor integrated circuit (IC) devices, such as radio frequency (RF) IC devices, include stacked metal layers. Some RF ICs employ both metal layers and ultra thick metal (UTM) layers in which the UTM layers have a greater thickness than the metal layers. For example, while some metal layers range from about 1,000 to about 8,000 Å in thickness, some UTM layers range from about 8,500 Å to about 38,000 Å in thickness. In some RF ICs, one or more UTM layers are formed over the metal layers separated by insulating layers except where portions of the metal and UTM layers are connected by one or more vias.